Preparation method of rubber surface TiCr / Cu multilayer composite film

Abstract

The invention discloses a preparation method of a rubber surface TiCr / Cu multilayer composite film, which comprises the following steps: firstly, depositing a Ti metal bonding layer on the surface of a rubber substrate by using a magnetic filter cathode arc deposition technology, and then sequentially depositing a TiCr gradient mixing layer, a TiCrCu gradient bearing layer and a surface layer formed by alternating TiCr layers and Cu layers by combining a high-power pulse magnetron sputtering technology. The friction coefficient of the obtained TiCr / Cu multilayer composite film is reduced to about 0.3 relative to 1.3 of bare rubber.

Description

Technical Field

[0001] The invention relates to a method for preparing a TiCr / Cu multilayer composite film on a rubber surface, and belongs to the fields of solid lubricating materials and tribology. Background Art

[0002] There are a large number of rubber sealing devices in modern industrial equipment to prevent leakage of working media and intrusion of external dust and foreign objects. Once the sealing medium leaks, it will directly endanger personal safety and bring huge economic losses. At present, most sealing leakage accidents are related to the sealing failure of seals. Therefore, sealing failure of seals is one of the key common technical problems of mechanical equipment sealing systems. When rubber and metal are matched, the friction coefficient is extremely high (µ>1). The friction heat generated by high friction can easily cause the rubber seal to soften and quickly wear out and fail, causing the high-pressure sealing medium to leak from the damaged part and the seal to fail, affecting the safe and reliable service of the equipment. Therefore, solving the problem of wear and failure of rubber seals must start with reducing friction.

[0003] Patent CN201810736543.8 proposes a method for preparing graphene-modified fluoroether rubber, which uses flake graphene to in-situ grow needle-shaped zinc oxide micro-nano composites, and uses the needle-shaped oxides in the composites to be interspersed in the graphene sheets to inhibit the agglomeration between components. Through the synergy of multi-form components, the friction, wear and thermal conductivity are significantly improved, while maintaining good mechanical strength. However, the rubber obtained by this method is affected by the quality of the graphene itself, and the production line needs to be greatly improved, which is too costly. Patent CN 201811485726.3 discloses a method for preparing a polymer-like carbon film for anti-wear and friction reduction modification of fluororubber surface and a fluororubber obtained by using the carbon film, which includes using fluororubber as a base material and sputtering and cleaning the base; using medium-frequency magnetron sputtering deposition technology to bombard and sputter a graphite target to generate a mixed plasma; while sputtering the target, turning on a medium-frequency pulsed DC bias power supply to accelerate the mixed plasma to the substrate and deposit it on the fluororubber substrate. However, this method does not solve the problem of high hardness, poor performance, and shedding of the carbon film due to long-term placement. Patent CN202110538435 provides a method for preparing an ultra-high wear-resistant rubber-based composite material with a carbon film on a continuous structure surface, which is to pre-clean the rubber substrate and then perform micro-nano texturing, and then bombard the micro-nano textured rubber matrix with nitrogen plasma and argon plasma in turn for cleaning and activation, and then deposit a carbon film on the surface of the rubber substrate to obtain an ultra-high wear-resistant rubber-based composite material with a continuous structure. This method of constructing micro-nano textures can effectively reduce the internal stress of the carbon film, improve its bonding strength and service life, but there are challenges in how to control the preparation of the texture and achieve mass production.

[0004] The invention takes into account the problem of hardness and brittleness of carbon film, benefits from the good flexibility of TiCr / Cu film and the lubricity of copper, and proposes a method for preparing TiCr / Cu multilayer composite film on rubber surface. Summary of the invention

[0005] The invention discloses a method for preparing a TiCr / Cu multilayer composite film on a rubber surface, so as to solve the problems in the prior art that the carbon film is hard and brittle, easy to fall off and difficult to be applied in engineering.

[0006] 1. Preparation of TiCr / Cu multilayer composite film on rubber surface The method for preparing the TiCr / Cu multilayer composite film on the rubber surface of the present invention first uses a magnetic filtration cathode arc deposition technology to deposit a Ti metal bonding layer (A) on the surface of the rubber substrate, and then combines a high-power pulsed magnetron sputtering technology to sequentially deposit a TiCr gradient mixed layer (M), a TiCrCu gradient bearing layer (TC2), and a surface layer composed of alternating TiCr layers (TC1) and Cu (C) layers. The specific process is as follows: 1) First, fix the cleaned rubber substrate in the vacuum chamber and evacuate to 2×10 -4 Pa; a Cu target and a Cr target for magnetron sputtering are installed in the vacuum chamber, a curved magnetic filter tube is connected between the Cu target and the Cr target, and a Ti arc target for magnetic filtration cathode arc deposition is fixed at the other end of the curved magnetic filter tube; the rubber substrate is one of nitrile rubber, fluororubber and silicone rubber; 2) Turn on the Ti arc target for magnetic filtration cathode arc deposition, set the Ti target current to 75~85A, bias voltage to 350~400V, Ar gas pressure to 0.3~0.5Pa, rubber substrate speed to 1~2r / min, deposition time to 15~20min; the coil current on the 135° magnetic filtration elbow close to the Ti arc target for magnetic filtration cathode arc deposition is 20~30A, the central magnetic field strength is 80~90 Gauss, the coil current close to the vacuum chamber is 30~40A, and the central magnetic field strength is 100~110 Gauss; 3) Keep the other conditions unchanged, adjust the Ti arc target current to 120~130A, turn on the Cr target for magnetron sputtering, gradually increase from 0A to 12A within 20min, bias voltage 65~75V, deposition time 20~25min; 4) Keep the other conditions unchanged, turn on the Cu target for magnetron sputtering, set the current to 5~10 A, the bias voltage to 65~75 V, and the deposition time to 10~15 min; 5) Deposit the TiCr layer first and then the Cu layer, alternating for 140 to 160 cycles; when depositing the TiCr layer, turn off the Cu target for magnetron sputtering, keep the process parameters of the Ti arc target for magnetic filtered cathode arc deposition and the Cr target for magnetron sputtering unchanged, and deposit for 5 to 10 minutes; when depositing the Cu layer, turn off the Ti arc target for magnetic filtered cathode arc deposition and the Cr target for magnetron sputtering, keep the process parameters of the Cu target for magnetron sputtering unchanged, and deposit for 5 to 10 minutes.

[0007] Figure 1 The present invention is a schematic diagram of the structure of the TiCr / Cu multilayer composite film on the rubber surface, wherein S is a rubber substrate. A Ti metal bonding layer (A) is first deposited on the surface of the rubber substrate (S) by using a magnetic filtration cathode arc deposition technique, and then a TiCr gradient mixed layer (M), a TiCrCu gradient bearing layer (TC2) and a surface layer composed of alternating TiCr layers (TC1) and Cu (C) layers are sequentially deposited in combination with a high-power pulsed magnetron sputtering technique. Through multi-layer regulation, the high hardness of TiCr and the lubricity of Cu are fully utilized to form a lubricating layer with high strength and deformation resistance, and the lubricating layer has excellent wear resistance and fatigue resistance.

[0008] 2. Properties of TiCr / Cu multilayer composite films on rubber surface 1. Bonding strength The bonding force of the film was measured to be 52 N using the spherical scratch method.

[0009] 2. Friction performance 2.1 Friction performance in vacuum environment The friction test was carried out using a ball-on-disk friction tester with a load of 3 N and a speed of 600-1000 rpm in a vacuum environment (vacuum degree 4×10 -3 The friction coefficient was tested in 2000 rpm and the data are listed in Table 1. Compared with the friction coefficient of uncoated rubber (1.26), the friction coefficient was reduced to about 0.23~0.20.

[0010] 2.2 Friction performance in dry atmosphere The friction coefficient was tested in dry atmosphere (humidity <10%) using a ball-on-disk friction tester with a load of 3 N and a speed of 600-1000 rpm. The data are listed in Table 1. Compared with the friction coefficient of uncoated rubber (1.32), the friction coefficients were reduced to about 0.25-0.21.

[0011] 2.3 Friction performance in nitrogen environment The friction coefficient was tested in a nitrogen environment using a ball-on-disk friction tester with a load of 3 N and a speed of 600-1000 rpm. The data are listed in Table 1. Compared with the friction coefficient of uncoated rubber (1.29), the friction coefficients were reduced to about 0.27-0.25.

[0012] 2.4 Friction performance in 3.0% humid air environment The friction coefficient was tested using a ball-on-disc friction tester with a load of 3 N and a speed of 600-1000 rpm in a 3.0% humid air environment, and the data are listed in Table 1. Compared with the friction coefficient of uncoated rubber (1.32), the friction coefficient was reduced to about 0.28-0.25.

[0013] Table 1 Friction properties of TiCr / Cu multilayer films on rubber surface Compared with the prior art, the present invention has the following beneficial effects: The use of flexible metal film avoids the problems of poor bonding and fatigue resistance caused by the high hardness and brittleness of carbon film. The efficiency of depositing metal film is more than 5 times higher than that of carbon film, which greatly saves costs and is conducive to promoting the application of lubricating film in the rubber industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the TiCr / Cu multilayer composite film on the rubber surface of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with specific embodiments. The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art. In the following embodiments, the various processes and methods not described in detail are conventional methods well known in the art. Example

[0016] This embodiment uses a rubber substrate of 20 mm×20 mm fluoroether rubber or nitrile rubber (surface finish Ra<200 nm, thickness 2 mm); the preparation process is as follows: 1) First, fix the cleaned rubber substrate in the vacuum chamber and evacuate to 2×10 -4 Pa; then Ar gas is injected, and the gas pressure is maintained at about 0.35 Pa; Cu target and Cr target for magnetron sputtering are installed in the vacuum chamber, a 135° magnetic filter elbow is connected between the Cu target and the Cr target, and a Ti arc target for magnetic filter cathode arc deposition is fixed at the other end of the 135° magnetic filter elbow; 2) Turn on the Ti arc target, set the Ti arc target current to 80A, the bias voltage to 350-400V, the magnetic filter coils close to and far from the Ti arc target to 25A and 35A respectively, the rubber substrate speed to 1r / min, and the deposition time to 15min; 3) Keep the other conditions unchanged, adjust the Ti arc target current to 125A, turn on the Cr target at the same time, gradually increase from 0A to 12A within 20min, bias voltage to 70V, deposition time to 20min; 4) Keep the other conditions unchanged, turn on the Cu target, set the current to 5A, the bias voltage to 70V, and the deposition time to 10min; 5) Deposit the TiCr layer first and then the Cu layer, alternating for 150 cycles; when depositing the TiCr layer, turn off the Cu target, keep the process parameters of the Ti target and the Cr target unchanged, and deposit for 5 minutes; when depositing the Cu layer, turn off the Ti target and the Cr target, keep the process parameters of the Cu target unchanged, and deposit for 5 minutes.

[0017] The structural characterization and performance evaluation were as described above.

Claims

1. A method for preparing a TiCr / Cu multilayer composite film on a rubber surface, characterized in that: First, a Ti metal bonding layer is deposited on the surface of the rubber substrate using magnetic filtration cathode arc deposition technology, and then a TiCr gradient mixed layer, a TiCrCu gradient bearing layer, and a surface layer composed of alternating TiCr layers and Cu layers are deposited in sequence using high-power pulsed magnetron sputtering technology. The specific process is as follows: 1) First, fix the cleaned rubber substrate in the vacuum chamber and evacuate to 2×10 -4 Pa; a Cu target and a Cr target for magnetron sputtering are installed in the vacuum chamber, a curved magnetic filter tube is connected between the Cu target and the Cr target, and a Ti arc target for magnetic filtration cathode arc deposition is fixed at the other end of the curved magnetic filter tube; 2) Turn on the Ti arc target for magnetic filtration cathode arc deposition, set the Ti target current to 75~85A, bias voltage to 350~400V, Ar gas pressure to 0.3~0.5Pa, rubber substrate speed to 1~2r / min, and deposition time to 15~20min; 3) Keep the other conditions unchanged, adjust the Ti arc target current to 120~130A, turn on the Cr target for magnetron sputtering, gradually increase from 0A to 12A within 20min, bias voltage 65~75V, deposition time 20~25min; 4) Keep the other conditions unchanged, turn on the Cu target for magnetron sputtering, set the current to 5~10 A, the bias voltage to 65~75 V, and the deposition time to 10~15 min; 5) Deposit the TiCr layer first and then the Cu layer, alternating for 140 to 160 cycles; When depositing the TiCr layer, turn off the Cu target for magnetron sputtering, keep the process parameters of the Ti arc target for magnetic filtered cathode arc deposition and the Cr target for magnetron sputtering unchanged, and deposit for 5 to 10 minutes; when depositing the Cu layer, turn off the Ti arc target for magnetic filtered cathode arc deposition and the Cr target for magnetron sputtering, keep the process parameters of the Cu target for magnetron sputtering unchanged, and deposit for 5 to 10 minutes.

2. The method for preparing the TiCr / Cu multilayer composite film on the rubber surface as claimed in claim 1, characterized in that: In step 1), the rubber substrate is one of nitrile rubber, fluororubber and silicone rubber.

3. The method for preparing the TiCr / Cu multilayer composite film on the rubber surface as claimed in claim 1, characterized in that: In step 2), the coil current on the curved magnetic filtration tube close to the Ti arc target for magnetic filtration cathode arc deposition is 20-30A, and the central magnetic field strength is 80-90 Gauss; the coil current close to the vacuum chamber is 30-40A, and the central magnetic field strength is 100-110 Gauss.

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